Sexual Selection, Resource Distribution, and Population Size in Synthetic Sympatric Speciation

Abstract

Speciation is one of the most fundamental and important processes in evolutionary biology, resulting in the panoply of biological diversity found in the natural world. Speciation likewise has profound implications for artificial life, evolutionary computation, and evolutionary robotics, yet a great many aspects of it remain unexplored. Traditionally, speciation was mainly viewed as taking place allopatrically. More recently, sympatric speciation, which does not require geographic isolation, has been studied. Sympatric speciation raises a number of interesting questions with regard to how and why sympatric populations diverge, some of which we address with a 2x2x2 factorial study that considers the factors of sexual selection, resource distribution, and population size. Our hypotheses were evaluated using a synthetic environment inspired by life on the Galápagos Islands. In particular, the wet and dry season dynamics were modeled to produce the intense selection pressure found there. Our results provide direct evidence for the importance of both female mate choice and resource availability on speciation. They also suggest that the greater stability afforded by larger populations can lead to subpopulations between which gene flow is reduced.